Alcohol mixtures adapted for use in making detergent sulfates

ABSTRACT

HIGHER ALCOHOL COMPOSITIONS ARE DISCLOSED WHICH ARE PRIMARILY MIXTURES OF MYRISTYL, PALMITYL AND STEARYL ALCOHOLS CONTAINING SMALL QUANTITIES OF ALCOHOLS OF LOWER MOLECULAR WEIGHT. THESE COMPOSITIONS CAN BE USED IN MAKING HIGH FOAMING MIXTURES OF ALKYL SULFATES.

United. States Patent Office 3,598,747 Patented Aug. 10, 1971 US. Cl.252-182 5 Claims ABSTRACT OF THE DISCLOSURE Higher alcohol compositionsare disclosed which are primarily mixtures of myristyl, palmityl andstearyl alcohols containing small quantities of alcohols of lowermolecular weight. These compositions can be used in making high foamingmixtures of alkyl sulfates.

CROSS REFERENCE TO RELATED APPLICATIONS This application is acontinuation-in-part of our copending application Ser. No. 558,237,filed June 17, 1966, now abandoned, which is a continuation-in-part ofapplication Ser. No. 277,078, filed May 1, 1963, now abandoned.

This invention relates to fatty alcohol compositions. More particularly,the invention relates to a synthetic mixture of fatty alcohol componentshaving particularly beneficial properties and not heretofore made oravailable by conversion of naturally occurring materials. Moreparticularly, the invention relates to a mixture of alcohols having asubstantial proportion of myristyl alcohol, or tetradecanol and being apreferred and more effective substitute for alcohols derived fromnaturally occurring tallow.

Heretofore, the synthetic detergent industry in the United States hasbeen predominantly based upon surface active agents derived from severalparticular sources, viz,

alkyl aryl sulfonates derivatives of naturally occurring fats,including, particularly, coconut oil and animal tallow.

The alkyl aryl sulfonates are a substantial source of detergentcomponents, but there is indication that these are unsatisfactory forcertain reasons, and it is believed that their percentage of the rawmaterial market will decrease in the future. The naturally occurringfats; however, are particularly beneficial in that they are readilysusceptible to conversion to surface active agents which have certainbenefits, relative to the alkyl aryl sulfonates. These benefits are thatsuch derivatives do not exhibit the branching which is so common amongthe alkyl radicals of the alkyl aryl sulfonates. The alkyl arylsulfonates having this high degree of branching are believed moreresistant to biodegradation in industrial and domestic sewage efiluents,and this resistance has created certain problems to the extent thatlegislation has been enacted in foreign countries or proposed in theUnited States, which in effect, limits the use of the alkyl arylsulfonates. On the other hand, the derivatives from the identifiednaturally occurring fats are straight chain materials, predominantly,and are more susceptible to biodegradation and also are extremelyefiicient detergent components.

The type of processing to convert the above-mentioned fats to detergentcomponents is widely varied, but for present purposes, can be summarizedby saying that a large fraction of these materials are converted to thecorresponding alcohol components or mixtures and are subsequentlytreated, for example, by sulfation, to form desirable detergentcomponents. Another technique for conversion of the resultant alcoholmixtures involves the reaction with a plurality of moles of alkyleneoxide, especially ethylene oxide, and the polyether hydroxy compoundresultant, or mixtures of compounds, can be used as components as such,or can also be treated by sulfation or sulfonation.

Generally, the utility of the naturally occurring fats, employed asabove outlined, is limited by several factors. For example, the relativeproportions of components in each of these fats, or in the alcoholsderived therefrom, are essentially fixed and not variant, as theyrepresent the result of natural synthesis. Thus, coconut oilpredominates in components having 12 through 16 carbon atoms permolecule, so that the alcohols therefrom predominate in lauryl throughpalmityl alcohols. On the other hand, the alcohols derived from animalfats are predominantly alcohols of 16 and 18 carbon atoms. In some products, the 18 carbon atom alcohol, instead of predominating in thesaturated compound, includes substantial quantities of the compoundhaving one unsaturated double bond therein.

Each of the above described naturally occurring fats has particularlydesirable attributes with respect to subsequently manufactureddetergents. The relatively invariant compositions of these fats, and ofthe alcohols derived therefrom, does create some limitations withrespect to most effective and economical manufacture. Thus, in the caseof coconut oil alcohol, the quantities of individual alcohols rank asfollows:

lauryl lauryl myristyl palmityl In other words, the predominantcomponent is the 12 carbon atom alcohol, followed by the 14 and 16 inthat order. With respect to alcohols derived from tallow, thepredominant alcohols are the 18 carbon atom components, followed by the16, with only very minor quantities of the 14 carbon atom alcohol. Thus,the presently available natural fats do not provide a substantial sourceof mixtures rich in 14 and 16 carbon atom alcohols, viz, myristyl andpalmityl alcohols. These two alcohols provide properties such that theresultant detergents partake of the particular benefits of detergentsmade from coconut oil alcohol, as well as detergents made from thetallow alcohols. The economics of the industry have dictated that thesenatural fats be processed as unitary mixtures, as the resolution ofresultant alcohol mixtures into individual pure alcohol components wouldbe prohibitive in cost and would also mean that the less desiredindividual components would not find ready usage. Hence, for practicalpurposes there has not heretofore been available an efficient andeconomical source of alcohols which are high in myristyl and palmitylalcohols, because of the relatively invariant compositions of naturallyoccurring raw materials.

The object of the present invention is to provide. a synthesized alcoholmixture which is essentially freed of the limitations on compositionheretofore experienced. More particularly, an object of the presentinvention is to provide a new alcohol product, high in myristylalcohols, and a particularly beneficial starting material for detergentproducts. More particularly, an object of the invention is to provide anew composition derived by synthetic techniques as describedhereinafter, wherein the preponderance of the mixture consists of the14-18 canbon atom alcohols, that is, myristyl, palrnityl and stearylalcohols. Other objects will appear hereinafter.

The fatty alcohols of the present process are generated by making atrialkyl aluminum mixture, then oxidizing said trialkyl aluminumcomponents to aluminum alkoxides, and then hydrolyzing said aluminumalkoxides with water or acidified water, whereby a mixture of alcoholsaccording to the present invention and an aluminum salt of an inorganicacid are produced. The product of the invention diifers appreciably fromany alcohol mixture obtained from naturally occurring fats or fatty oilsand is further significantly desirable in exhibiting high qualitystandards with respect to a variety of experimental criteria, forexample, the acid value, the unsaturation, carbonyl oxygen and estercontent and certain other attributes.

The product of the present invention can be made by several differentspecific variants within the above described general procedure. Aparticularly preferred manufacturing method, as described more fullyhereinafter, results in the conjoint production of the product with analcohol stream corresponding essentially to an alcohol derived from acoconut oil. It is found that the high myristyl alcohol product of thepresent invention can be thus jointly made with coconut oil, so that therelative proportions are from about 2 to 6 or 7 parts by weight ofcoconut oil alcohol per part of the high myristyl alcohol product.

In addition to the principal cuts which are actually provided, theinitial product mixture includes relatively minor components of alcoholsof lower than 12 carbon atoms. However, it is surprisingly discoveredthat a product is derivable which differs greatly in the weight ormolecular weight distribution from that which would be predicted oranticipated by any of the prior art.

In the preferred mode of preparing the present product, as explainedabove, a crude mixture is obtained, from which is separated thesynthetic coconut oil alcohol fraction and the desired high myristylalcohol product. An illustrative, but non-limiting composition of thecrude alcohol, made according to the above mentioned preferred route, isas follows:

Alcohol: Weight percent Ethyl 1 Butyl 1 Hexyl 1.5 Octyl 3.3 Decyl 7.8Dodecyl or lauryl 34.8 Tetradecyl or myristyl 25.8 Hexadecyl orpalrnityl 16.4 Octadecyl or stearyl 8.7 Eicosyl or arachidyl and higher3 The crude stream, of which the foregoing is an illustrativecomposition, is fractionated into the desired high myristyl alcoholfraction, a fraction high in lauryl alcohol, generally corresponding toa coconut oil alcohol, and a low alcohol fraction predominating in octyland decyl alcohols. Small amounts of lower-than-octyl, and higher thanstearyl alcohols are also separated.

The high myristyl alcohol product has an approximate composition rangeas given below:

Alcohol: Weight percent Myristyl 25-50 Palmityl 30-45 Stearyl 1530 Thisproduct is generally also limited to not over about 2 weight percent,each, of components lower and higher than those listed.

The intermediate cut, corresponding generally to a coconut oil alcohol,is controlled within the following range of compositions:

Alcohol: Weight percent Lower than lauryl max 3 Lauryl 60-7O Myristyl20-30 Palmityl ,max 10 Higher alcohols max 2 The foregoing compositionsare on the basis of the alcohol analysis, i.e. exclusive of otherimpurities, principally hydrocarbons, which may be present inproportions of up to about four percent without seriously affecting theproperties of the products. The hydrocarbon impurities are generallyalkane and alkene components.

In addition to the distribution of the alcohol components in theproduct, and in the synthetic coconut oil alcohol which is customarilyconcurrently made, various other recognized quality tests are frequentlyapplied. Generally, such tests or product criteria are determined byprocedures of the American Oil Chemists Society, and some of these arereferred to below.

Acid value.The free fatty acids or acid values of the streams aredetermined by the A.O.C.S. method Ca 5a- 40. It is expressed in terms ofmilligrams of potassium hydroxide necessary to neutralize one gram ofsample.

Iodine value.The iodine value is significant in indicating the degree ofunsaturation of a particular product. It is determined by A.O.C.S.method Cd 1-25, and is expressed in terms of centigrams of iodineabsorbed per gram of sample.

Ester value.The ester content is determined as the difference betweenthe A.O.C.S saponification value (Cd 3-25) and the acid value, asalready defined.

Moisture value.The moisture value is determined according to A.O.C.S.procedure Ca 2a55.

Color.Clarity or color is usually determined using. for example, theAmerican Public Health Association scale (A.P.H.A.).

Carbonyl oxygen.The total amount of carbonyl oxygen present in thesample is determined using, for example, the method described inAnalytical Chemistry 31, 760 (1959).

Hydroxyl value.The measure of the amount of hydroxyl value of a sampleis determined according to A.O.C.S. procedure Cd 13-60. It is defined interms of milligrams potassium hydroxide equivalent to the hydroxylcontent of one gram of sample.

Hydrocarbon impurity,As previously mentioned. another quality criterionis the amount of hydrocarbon impurity. This is efficiently determined bygas chromatography.

Among the foregoing quality or identifying tests, the amount of esters,carbonyl oxygen and the hydroxyl value of the product are probably themost important. The amount of discoloration or degradation of aspecimen, when exposed to strong sulfuric acid is frequently determined,particularly for the alcohols of the coconut oil type.

The most preferred form of the high myristyl alcohol product of thepresent invention is obtained in conjunction with about twice itsquantity of a product corresponding in general composition to a coconutoil alcohol. The composition of such a preferred high myristyl alcoholproduct is as given below:

Alcohol: Weight percent Lower than myristyl Not over about 1.5. Myristyl42:4. Palmityl 36:4. Stearyl 19:3. Higher than stearyl 2 max.

In addition to the foregoing compositions such preferred high myristylalcohol products exhibit additional high quality attributes, including,particularly in that the carbonyl oxygen content does not exceed about0.05 weight percent, and a hydroxyl value of at least 225, as mg. KOH/g.Further a total non-alcohol impurity concentration of not over about 3weight percent is experienced. Additional typical quality attributes ofless significance include the following:

Acid value Max. 1.0 mg. KOH/g. Iodine value Max. 1.0 cg. I /g.

Ester value Max. 1.5 mg. KOH/ g. Moisture Max. about 0.15 percent.

As already described the chemical reactions involved in preparing thealcohols of the present invention include the chain growth of ethyleneon a lower alkyl-trialkyl aluminum to obtain higher alkyl-trialkylaluminum compounds. These are then oxidized to aluminum alkoxidematerials which are then hydrolyzed by reaction with an aqueous acid andform thereby alcohols corresponding to the alkyl group and aluminumsalts corresponding to the acid of the aqueous acid used. The chaingrowth of ethylene on a lower alkyl-trialkyl aluminum compound is Wellknown, generally, but performing this operation in the heretofore knownconventional manner will not produce gross trialkyl aluminum mixtureshaving alkyl groups distributed by chain length as required for thepresent invention. Hence, if the conventional process sequence isobtained, the alcohols derived thereby will include substantialproportions of lower than desired alcohols than is required for mostelficient performance. When the above general or conventional procedureis followed, the alcohol mixture of the present invention is separatedby fractionation, resulting in substantial quantities of alcoholcomponents outside the range of the desired product. The most preferredsynthesis, however, utilizes a novel process wherein the alkyl groups ofthe trialkyl aluminum intermediate stream are generated inanti-statistical, or non- Poisson proportions. The characteristics ofthis highly preferred preparatory process are summarized below.

The essential feature of the preferred preparatory process is the use ofat least two displacement processes, whereby the distribution of alkylgroups to a non-statistical spectrum is achieved. In carrying out anembodiment of such a process, the operations include the followingsteps:

The ethylene to be utilized in chain growth is divided into twoportions, and only a fraction usually of about one-half to three-fourthsis reacted with the initial lower alkyl-trialkyl aluminum, preferablytriethyl aluminum, in a first chain growth reaction.

The chain grown trialkyl aluminum effluent from the first chain growthreaction is then subjected to a displacement reaction with a mixture ofolefins predominating in olefins of less than 12 carbon atoms, whereby adisplacement product mixture from this first displacement reaction isobtained which includes olefins enriched in higher olefins of above 12carbon atoms and trialkyl aluminum mixture enriched in alkyl groups ofless than 12 carbon atoms.

The trialkyl aluminum mixture from the first displacement reaction isthen subjected to a second chain growth reaction with the remainder ofthe ethylene to be reacted.

The trialkyl aluminum from the second chain growth reaction is thenprocessed in a second displacement reaction, wherein reaction is carriedout with olefins, concen trated in olefins of 12 and higher carbonatoms, as a result of which the trialkyl aluminum fed is converted totrialkyl aluminum mixtures appreciably enriched in alkyl aluminum groupsof 12 and higher carbon atoms.

The trialkyl aluminum thus obtained exhibits a unique non-Poissondistribution of alkyl group lengths. This mixture is then oxidized withan oxygen containing gas to convert a substantial proportion of thealkyl aluminum bonds to the corresponding alkoxide aluminum bonds, andthe oxidized mixture is then hydrolyzed or reacted with a dilute aqueousadded acid to form the desired alcohol mixture. Upon separation ofcertain impurities from the resultant alcohol mixture, it is then readyfor fractionation and separation of a cut corresponding to a coconut oilalcohol, and the desired myristyl alcohol fraction of the presentinvention.

Instead of employing two separate chain growth operations, as describedabove, a variation of the process utilizes a single chain growthreaction, but processes a mixture of fresh low alkyl trialkyl aluminumand trialkyl aluminum, which is generated in a first displacementreaction. In all of these preferred methods of generating thenon-Poisson, trialkyl aluminum mixtures from which the desired alcoholproduct is obtained, at least two displacement reactions are carriedout, utilizing circulating olefin streams to continually adjust theidentity and proportions of the alkyl groups of the trialkyl aluminumstream.

In a typical operation, according to the preferred process firstdescribed above, the crude alcohol mixture, from which the preferredmyristyl-rich alcohol product is derived, has the following composition:

Alcohol: Weight percent Ethyl 0.3 Butyl 0.4 Hexyl 1.4 Octyl 3.2 Decyl6.7 Lauryl 37.2 Myristyl 26.7 Palmityl 15.4 Stearyl 6.4 Higher thanstearyl 2.3

In addition to the preferred high myristyl alcohol fractron alreadydescribed, a mixture corresponding to a coconut oil fraction isseparated having the following approximate composition range:

Alcohol: Weight percent Lower than lauryl max 3 Lauryl 65 :2 Myristyl 25+4 Palmityl 71-3 Stearyl and higher max 1 Alcohol: Weight percent Lowerthan myristyl 0.3 Myristyl 2.5 Palmityl 27.2 Stearyl 69.2 Higher thanstearyl 0.8

From the foregoing it is seen that alcohols from animal fats arevirtually devoid of the very desirable myristyl alcohol componentwhereas the product of the present invention contains from one-fourth toabout one-half myristyl alcohol content and in the particularlypreferred composition, about 42 percent of this component.

The compositions of the present invention are readily reacted at F. withchlorosulfonic acid to produce alkyl sulfates for use in detergents. Thereaction proceeds according to the following equation and theequilibrium is favored for the desired product by low temperatures ofthe order of 100 F.

The equilibrium is not favorable to this reaction with palmityl andstearyl alcohols per se because of their high melting point.

Sodium alkyl sulfate detergents are obtained by reacting the alkylsulfate with caustic. Samples of such material are tested and rated forvarious properties using standard techniques. One technique is a foamtest identified as the Ross-Miles test. This compares the amount of foamobtained from different materials at selected temperatures andconcentrations. An important temperature for this is 40 C. which isrepresentative of temperatures used in hand dishwashing operations. A0.2 wt. percent concentration represents the start of a dishwashingwhile the 0.1 wt. percent represents the end of effective dishwashingbefore adding new cleaning agent. When the test is made according to aconventional procedure, foam heights are as follows.

The 0.1 percent data for the blend, for example, shows a foam heightimprovement of 13.3 percent over that predictable from the components.

EFFECTIVENESS CALCULATED FROM COMPONENTS [150 mm. foam height] Percent-Individual age, effec- Fraetion foam tiveness Myristyl, mm 0. 4 185 74.

Palmityl, mm... 0. 4 150 00.0

Stearyl, mm 0. 2 80 16.0

Total, mm 150.0

Actual effectiveness 1 70 Difference Percentage improvein prediction l3.3

The 0.1 percent data shows a foam height improvement of 18.4 percentover that predictable from the components.

EFFECTIVENESS CALCULATED FROM COMPONENTS [152 mm. foam height] Percent;

Individual age, efiec- Fraction foam tivencss Myristyl, mm 0. 4 185 74.0

Palmityl 0. 4 175 70.0

Stearyl, nun 0. 2 40 8.0

Total, mm 152.0

Actual efieetiveness 180 Difference f f 28 Percent improvement 28prediction 100 18. 4

From the foregoing it is evident that myristyl (C alcohol provides themost profuse foaming cleaning agents of this type and that the blend isalmost as good as that individual material despite the fact that theindividual characteristics of the components, particularly stearyl andto a smaller extent, palmityl, are much lower.

The data also show that stearyl alcohol is of little value per se;however, when used in a composition (mixture) according to the presentapplication, it is almost as good as myristyl alcohol and that theoverall value for the mixture is better than that of any of theindividual components other than myristyl.

The data show that the present compositions have a superiority of about15 percent over the percentage-eflectiveness sums for the components. Inother words, the effectiveness of the combination based on the claimedalcohol composition exceeded the sum of effectiveness of the componentswhen tested individually.

Another important criteria in this connection is the detersive(cleaning) ability. Again a standard test procedure was used, with aLaunder-O-Meter of US. Testing Company using soiled test cloths. Thistest was made at F. which is a typical home laundering temperature. Thedetergent sodium alkyl sulfate was used at a 0.1 percent concentration(weight) with 0.05 percent sodium metasilicate as builder.

Increase in reflect- Detergent sodium alkyl sulfate: ance of the washAlkyl Lauryl (C 17.00

From this it is evident that detergency also peaks at c under theconditions selected and that the composition is practically equal to thepeak detergency in cleaning efficiency despite the content of stearyl(C18).

Similar desirable characteristics are found with the compositions inpreparing detergent bars for personal use. Profuse foam and goodcleaning properties are obtained in hand washing and bathing.

Palmityl and stearyl in effect require a solubilizing action to makethem useful in applications such as the above. Myristyl alcohol providesthis effect in the present compositions. In prior art compositions basedon efficient and economical utilization of starting materials it isnecessary to obtain the solubilizing effect through unsaturatedalcohols, particularly C The use of unsaturated alcohols has significantadverse effects since they impart undesired properties such as color,odor, rancidity, and instability to heating.

EXAMPLE I A typical composition of 40 percent myristyl alcohol, 40percent palmityl alcohol and 20 percent stearyl alco 1101 (by weight)was made and tested using 0.2 weight percent concentration of the sodiumalkyl sulfate pastes of the alcohols in a standard water solution ofppm. (parts per million) hardness as equivalent calcium carbonate. Thehardness was achieved by use of a mixture of calcium chloride andmagnesium sulfate to provide a calcium cation/ magnesium cation weightratio of 3/2. The temperature of each solution during the test was 95 F.

In the test the activity of a sodium alkyl sulfate paste is related tothe height of the foam it produces. In other words, the higher the foam,the more active the substance under test. In addition, it is desirablethat the foam exhibit stability and therefore the height of the foam ismeasured not only as soon as it has beefi formed but also after standingfor 5 minutes.

The results of the tests are tabulated hereinafter.

Foam height (millimeters) After 5 Initial minutes Composition, 10/10/20r 1-10 l25 EXAMPLE II In a comparative test, a sodium alkyl sulfatedetergent derived from a different starting alcohol mixture was testedas in Example I.

EXAMPLE III Example II was repeated in another comparative example usinga sodium alkyl sulfate paste derived from another starting alcoholmixture.

Foam height (millimeters) Mixture, parts by After Comp orient weightInitial minutes g y y g8 ahnity Stearyl 4 45 Total 100 The results ofExamples II and III are clearly inferior to those of Example I.

What is claimed is:

11. A synthetic fatty alcohol mixture having the following compositionon a hydrocarbon impurity free basis:

Alcohol: Weight percent Lower than myristyl Not over about 2. Myristylto 50. Palmityl to 45.

Stearyl 15 to 30. Higher than stearyl Not over about 2.

2. A synthetic fatty alcohol mixture having the following composition ona hydrocarbon impurity free basis:

Alcohol: Weight percent Lower than myristyl max 1.5 Myristyl 42:4Palmityl 36:4 Stearyl 19:3 Higher than stearyl max 2 said mixture beingfurther defined by having the following attributes:

Carbonyl oxygen Max. 0.05 weight percent.

Hydroxyl Min. 225 as mg. KOH/ gram.

Total impurities Not over about 3 weight percent.

3. A synthetic fatty alcohol mixture having the following composition ona hydrocarbon impurity free basis:

10 Alcohol: Weight percent Lower than myristyl Not over about 2.Myristyl 25 to 50. Palmityl 30 to 45. Stearyl 15 to 30.

Higher than stearyl Total impurities Not over about 2. Not over about 4Weight percent.

4. A synthetic fatty alcohol mixture having the following composition ona hydrocarbon impurity free basis:

Alcohol: Weight percent Lower than myristyl Not over about 2. Myristyl25 to 50. Palmityl 30 to 45.

Stearyl 15 to 30. Higher than stearyl Not over about 2.

said mixture being further defined by having the following attributes:

Carbonyl oxygen Max. 0.05 weight percent.

Hydroxyl value Min. 225 as mg. KOH/ gram,

Total impurities Not over about 3 Weight percent.

5. A synthetic fatty alcohol mixture having the following composition ona hydrocarbon impurity free basis:

Alcohol: Weight percent Lower than myristyl max 1.5 Myristyl 42:4Palmityl 36:4 Stearyl 19:3 Higher than stearyl max 2 said mixture beingfurther defined by having the following attributes:

Iodine value Max. 1.0 cg. I gram.

Carbonyl oxygen Max. 0.05 Weight percent.

Hydroxyl value Min. 225 as mg. KOH/ gram.

Ester value Max. 1.5 mg. KOH/ gram.

Total impurities Not over about 3 weight percent.

References Cited UNITED STATES PATENTS 3,412,126 11/ 1968 Gautreaux260632X 2,865,859 12/1958 LuboWe 25256 2,486,921 11/1949 Byerly 2521382,166,315 7/1939 Martin.

OTHER REFERENCES Tallow & Coconut Fatty Alcohols From Procter & Gamble,Printed 10/ 1963.

LEON D. ROSDOL, Primary Examiner D. L. ALBRECHT Assistant Examiner US.Cl. X.R.

